Semiconductor fabrication techniques are in use to produce micromechanical structures from silicon wafers. Such micromechanical structures have the potential of mass production at a very low cost.
Illustrative of this particular technology is U.S. Pat. No. 4,598,585 to Boxenhorn, which discloses a planar micromechanical vibratory gyroscope adapted for small geometry configurations which may be constructed using semiconductor fabrication mass production techniques.
Further advances in micromechanical gyroscopic transducer technology are described in Applicant's co-pending U.S. Patent Application Ser. No. 07/143,515, filed Jan. 13, 1988, entitled METHOD AND APPARATUS FOR SEMICONDUCTOR CHIP TRANSDUCER which is incorporated herein by reference.
Other advances in micromechanical gyroscopic technology are described in Applicant's pending U.S. Patent Application Ser. No. 372,653 entitled BRIDGE ELECTRODES; and U.S. Patent Application Ser. No. 07/470,938 entitled MICRO-MECHANICAL DEVICE WITH A TRIMMABLE RESONANT FREQUENCY STRUCTURE AND METHOD OF TRIMMING SAME; all of which are incorporated herein by reference.
The infancy of monolithic micromechanical semiconductor gyroscopic transduction technology assures that significant advances will continue to be made with respect to implementation and application of the technology. As structures are implemented having increased sensitivity and accuracy, problem areas are identified and solutions defined. Presently, shortcomings with respect to "rippling" of an oxide support frame from which an outer flexure extends connecting a resonating structure thereto are observable. "Buckling" of inner flexures, results in undesirable large variations in a critical resonant frequency of a suspended gyroscopic element. Furthermore, surface bridge electrodes used for sensing and for rebalancing of a certain axis of a resonating structure have large capacitances to the substrate limiting effectiveness as signal pickoffs.